Rangers have captured a monster three-metre crocodile as they continue to hunt down the predator believed to have eaten an elderly woman with dementia.

Police believe Anne Cameron, 79, became disorientated after leaving her aged care facility in Port Douglas, north Queensland, and wandered into dense mangroves.

Officers found human remains, a walking stick with her name on it and a pile of her clothes at an inlet connected to a creek infested with large saltwater crocodiles.

Ms Cameron's devastated family conceded they were of the 'firm belief' Anne had 'passed away in tragic circumstances' as they waited for DNA testing to come back.

A spokesman for the Department of Environment and Heritage Protection said rangers were yet to capture the 'target' crocodile.

A police search for missing Alzheimer's patient Anne Cameron (pictured) has turned up a walking stick with her name on it, a pile of clothes and human remains

Police believe the 79-year-old became disorientated and wandered into dense mangroves in the Mowbray River (pictured), where a crocodile likely took her and ate her alive

Ms Cameron was last seen before she left her OzCare aged care facility (pictured) in Port Douglas, north Queensland, to take a walk on Tuesday afternoon

The 79-year-old, who has Alzheimer's disease, was last seen before she left her OzCare aged care facility to take a walk on Tuesday afternoon.

Her daughter Isabella Eggins, who has helped police and SES with the three-day search, admitted the family were convinced Ms Cameron was eaten alive.

'It is my deep regret to inform you that following an extensive search and the discovery of certain items as a resul­t of that search, we have the firm belief that my mother Anne Cameron has passed away in tragic circumstances,' she wrote.